Aperture Diaphragm in Blender 2.8
It's still there, just the name is changed :).
Now it's called  Align to Vertex Normal ✓



When setting up the constraint, change Mix to Add.
Otherwise the triangles won't line up later.



You can add the constraint to other objects using Object > Constraint > Copy Constraints. Just make sure, the constraint isn't on the circle itself :).